Changing output of `voting_approval`

Question

I am trying to write a function that takes a parameter that is a list of 4-element lists that represent approval ballots for a single riding; the order of the inner list elements corresponds to the order of the parties in a list of parties called PARTY_INDICES.

The party with the most number of 'yes' votes wins.

It should return a 2-tuple where the first element is the name of the winning party and the second element is a four-element list that contains the number of yes votes for each party. The order of the list elements corresponds to the order of the parties in PARTY_INDICES.

My code is:

def voting_approval(approval):
    parties = ['NDP','GREEN','LIBERAL','CPC']
    values = [0,0,0,0]
    for decision in approval:
        for no, item in enumerate(decision):
            if item == 'Yes':
                values[no] += 1
                total = [(values) for x in zip(approval)]

    return (parties[values.index(max(values))], total)

If I try:

voting_approval([['Yes', 'No', 'Yes', 'No'],['No', 'No', 'Yes', 'No']])

it spits out:

('LIBERAL', [[1, 0, 2, 0], [1, 0, 2, 0]])

but I want the result to be:

('LIBERAL', [1, 0, 2, 0])

Do you want the result to be `('LIBERAL', [1, 0, 2, 0])`? I think you have a typo. — Xymostech, Nov 30 '12 at 03:10
Can you elaborate a little bit more as to what your code is supposed to do.. — Diego Allen, Nov 30 '12 at 03:17
an example of "approval" would be [['Yes', 'No', 'Yes', 'No'],['No', 'No', 'Yes', 'No']]. It is just a random list with 4 elements, either yes or no — user1864828, Nov 30 '12 at 03:22
If I could make a suggestion, it would probably be a better idea to use the `True` and `False` keywords instead of `'Yes'` and `'No'`, respectively. — Nathan, Nov 30 '12 at 03:26

score 0 · Answer 1 · answered Nov 30 '12 at 03:26

0

Haven't tested extensively, but you could try:

In [7]: def voting_approval(approval):
   ...:     parties = ['NDP', 'GREEN', 'LIBERAL', 'CPC']
   ...:     values = [sum(1 if i == 'Yes' else 0 for i in group) for group in zip(*approval)]
   ...:
   ...:     return (parties[values.index(max(values))], values)
   ...:

In [8]: voting_approval([['Yes', 'No', 'Yes', 'No'],['No', 'No', 'Yes', 'No']])
Out[8]: ('LIBERAL', [1, 0, 2, 0])

This zips your lists together at the beginning, sums the Yes's and creates a new list with the totals, which is then used to pull out the required info. Happy to tweak if this isn't what you were looking for.

answered Nov 30 '12 at 03:26

RocketDonkey

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@user1864828 Happy to hear it :) Good luck with everything! – RocketDonkey Nov 30 '12 at 03:32
hey could i ask you one more question – user1864828 Nov 30 '12 at 03:37
im gonna post another question. i like your coding style. it would be awesome if you can help me with that one too :D – user1864828 Nov 30 '12 at 03:38
@user1864828 Ha, thanks :) Happy to take a look, but I'm definitely bottom tier around here - you'll get awesome solutions from the big boys. – RocketDonkey Nov 30 '12 at 03:50
hey @rocketdonkey could you look at this? http://stackoverflow.com/questions/13638807/changing-the-output-a-bit – user1864828 Nov 30 '12 at 05:04
1

@RocketDonkey "bottom tier"? humph - you don't do yourself justice ;) – Jon Clements Nov 30 '12 at 10:46
@JonClements Ha, well thank you. I would say 99% of what I know is based on answers from you and others here, so I'll keep riding your coattails as long as I can :) – RocketDonkey Nov 30 '12 at 16:57

Diego Allen · Answer 2 · 2012-11-30T03:33:55.193

0

You already have the amount of 'YES' per party stored in values. Just change your code as following.

def voting_approval(approval):
    parties = ['NDP','GREEN','LIBERAL','CPC']
    values = [0,0,0,0]
    for decision in approval:
        for no, item in enumerate(decision):
            if item == 'Yes':
                values[no] += 1

    return (parties[values.index(max(values))], values)

edited Nov 30 '12 at 03:33

answered Nov 30 '12 at 03:27

Diego Allen

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score 0 · Answer 3 · answered Nov 30 '12 at 03:32

You don't need that total var. values is already what you want.

def voting_approval(approval):
    parties = ['NDP','GREEN','LIBERAL','CPC']
    values = [0,0,0,0]
    for decision in approval:
        for no, item in enumerate(decision):
            if item == 'Yes':
                values[no] += 1

    return (parties[values.index(max(values))], values)

approvals = [
    ['Yes', 'No', 'Yes', 'No'],
    ['No', 'No', 'Yes', 'No'],
]

print voting_approval(approvals)

matt@wraith:~/Dropbox/Public/StackOverflow$ python 13638424.py 
('LIBERAL', [1, 0, 2, 0])

score 0 · Answer 4 · answered Nov 30 '12 at 03:34

I formatted it so you could see your code almost getting the answer.

def voting_approval(approval):
    parties = ['NDP','GREEN','LIBERAL','CPC']
    values = [0,0,0,0]
    for decision in approval:
        for no, item in enumerate(decision):
            if item == 'Yes':
                values[no] += 1
                total = [(values) for x in zip(approval)]

    return (parties[values.index(max(values))], total)

almostAnswer = voting_approval([['Yes', 'No', 'Yes', 'No'],['No', 'No', 'Yes', 'No']])
answer = [sum(a) for (a) in zip(almostAnswer[1][0], almostAnswer[1][1])]
print answer

You had the [sum(a) for a in zip(array1,array2)] down, but you were pointing to the wrong parts of the elements contained within approval - hence the need for [1][0] and [1][1].

score 0 · Answer 5 · edited Jun 20 '20 at 09:12

Essentially, if you think of each list of votes as a row in the approval list, what you want to do is tally or sum the number of yes votes that appear in the columns. A good way to do that is by transposing (or swapping the rows and columns) of this list of lists, and then total the number in of them each of the resulting rows.

Here's code showing how this is easily this is done. Note that the first item in the tuple returned is a list of party names, rather than a single value since ties are possible, as illustrated with the test values shown. I would also consider changing approval to approvals to reflect its content better.

approval = [['Yes', 'No', 'Yes', 'No'],
            ['No', 'No', 'Yes', 'No'],
            ['Yes', 'No', 'No', 'No'],]

def voting_approval(approval):
    parties = ['NDP','GREEN','LIBERAL','CPC']
    tallies = [sum(int(v =='Yes') for v in col) for col in zip(*approval)]
    most_yes = max(tallies)
    return ([party for i,party in enumerate(parties) if tallies[i] == most_yes], tallies)

print voting_approval(approval)

Output:

(['NDP', 'LIBERAL'], [2, 0, 2, 0])

Changing output of `voting_approval`

5 Answers5